1. Field of the Invention
The present invention concerns a device to circulate oil within a hollow shaft which revolves in an oil bath.
2. Description of the Prior Art
It is known that the lubrication of certain mechanical parts of gearboxes for vehicles or similar machines necessitates a penetration of oil into a hollow revolving shaft. Given that the centrifugal forces arise because the rotation of the shaft tends naturally to oppose the penetration of the oil into the hollow shaft, this lubrication is difficult to bring about by the conventional means of lubrication by immersion in the oil and the collection of oil splashes within a casing, and necessitates the oil being put under pressure.
When the output and the number of points to be lubricated in this way are large, the incorporation of a pressure lubricating assembly with a feed pump and distribution channels may be justified. On the other hand, when it is a question of lubricating an isolated component, it is advantageous to use a more compact device in order to carry out lubrication.
There exist a number of such prior art systems of small size and of the type with a built-in volumetric pump (vane, profile, gear, piston or other pumps). These systems present numerous disadvantages. For example, they comprise components rubbing one against another which are subject to wear and which are very sensitive to operating conditions, by being adversely affected by misalignments and the presence of impurities in the oil. In addition, so that these systems may operate in any direction of rotation of the hollow shaft, valves must be provided, further complicating the mechanism.